High-voltage power supply



March 17, 1953 P. s. GOODWIN 2,532,143

HIGH-VOLTAGE POWER SUPPLY Filed Feb. e, 195o 34 v JNVENToR.

35 /D/WL 5. ooow/M BY jm, ,5M

Patented Mar. 17, 1953 UNITED STATES Meur OFFICE HIGH-VOLTAGE POWER SUPPLY Application February 6, 1950, Serial No. 142,683

(Cl. 32l-l8) 8 Claims.

This invention relates to high voltage power supply and particularly, to a voltage regulator circuit adapted to develop two or more different regulated voltages selectable at will.

In many applications of electronics research or electronic industrial equipment, it is necessary to supply, at different times, regulated voltages of different values. A good example of this type of situation is to be found in the field of mass spectrometry. In one form of mass spectrometer, two dilferent voltages are required (for application to the accelerating electrodes) for analysis of materials of mass 2 to 100 and materials of mass 1 (hydrogen), respectively. In the particular instrument referred to, these two voltages are 210 and 510 voltages, respectively. This does not mean that these are the actual voltages impressed on the spectrometer accelerating electrodes but rather that these voltages are delivered to the voltage divider network of the mass spectrometer to permit analysis of materials in the mass ranges given. As is frequently the case, a single sample Linder analysis may include components in both mass ranges, and to accomplish a complete analysis, it is necessary7 to switch voltages while the sample is in the instrument. The voltage regulator circuit of the invention permits such a voltage switch avoiding the necessity of changing tubes or other circuit elements. Although the invention is hereinafter described with relation to this particular application and for convenience reference is had to the particular voltage values mentioned above, it will be apparent that the voltage regulator circuit is neither limited to this specific use nor to these particular voltages.

The voltage regulator circuit is adapted for connection to a source of unregulated voltage, conveniently coupled to the circuit through a multiple primary transformer by means of which unregulated voltages of differing magnitude may be fed to the circuit. A rectier is connected to the secondary of the transformer to convert the transformer output to an unregulated D. C. voltage. .The rectifier is, in turn, connected into a oating degenerative voltage regulator and amplier comprising a series regulator tube and a two-stage amplifier. An amplifier input voltage divider is connected across the regulated output and feeds a signal to the cathode of the first amplifier tube or stage proportional to fluctuations in the regulated output. A degenerative feed forward loop is connected between the unregulated input, i. e., between the rectifier and series regulator tube and the input divider to feed a small fraction of the unregulated input to the cathode of the iirst stage amplifier tube. The grid of the first amplification stage is connected to a reference voltage source. The effect of this apparent reversal of the grid cathode connection is to apply an out-of-phase signal from the ampliiier to the grid of the series regulator tube.

The regulator tube, amplifier, voltage reference, feed forward and voltage dividers are returned to a common bus to form a closed loop so that this portion of the circuit, which is hereinafter referred to as the basic circuit, may be conveniently operated at some arbitrary and preselected potential other than and including ground potential. For convenience, the basic circuit is designed to supply the lowest of a series of two or more regulated voltages by direct connection of the aforementioned bus to ground.

To obtain a second and higher regulated output voltage, there is interposed between the bus and ground one or more regulated sources of voltage as, for example, voltage regulator tubes. A switch is included to alternately connect the common bus directly to ground or to ground through the auxiliary regulated voltage sources. ln the same manner, additional regulated volt-- ages can be obtained by connecting the bus to ground through separate voltage sources of different magnitude while at the same time, varying the unregulated voltage input substantially in proportion to the desired incremental change in regulated output.

An important feature of the invention lies in the fact that the regulation achieved by the combination circuit, i. e., the basic circuit, plus auxiliary regulated voltage sources, is better than the predictable sum of the two regulator actions operating independently. This and other features of the circuit will be more clearly apparent from the following detailed description thereof taken in conjunction with the accompnying drawing in which:

Fig. 1 is a circuit diagram of the voltage regulator in simplified form; and v Fig. 2 is a circuit diagram showing the means for supplying unregulated voltage and showing the regulator circuit in more detail than in Fig. l.

Referring to Fig. l, the circuit includes unregulated D. C. voltage input terminals it and li. The terminal il is directly connected through a lead l2 to an output terminal I3 grounded at M. A regulator tube l5 having an anode 15A, a control grid iB and a cathode lGC is connected in series between an input lead Il and an output lead i8, terminating in an output terminal I9, the anode of the regulator tube being connected to input through lead ll and the cathode IGC of the tube being connected to the output lead I 8.

Amplifier tubes 2t, 2l, each having cathode, control grid and anode, are connected together with the anode of tube 2i! connected to the control grid of tube 2l to form a two-stage amplifier. The anode of tube 2I is connected to the control grid of the series regulator tube i5 and each of the anodes of tubes 2K3, 2l are connected through appropriate plate resistors to the lead I8 from whence plate current for the two tubes is derived.

A first or input voltage divider 2li is connected between the output lead i8 and a second voltage divider 25, which is connected between the inu put lead Il and a bus 25. The cathode of tube 2G is connected to the first voltage divider 2Q and receives a signal therefrom comprising the sum of fractional components of the regulated output voltage and of the unregulated input voltage. bodiment, a voltage regulator tube 28 is connected through a resistor 2l between the output lead IB and bus 2t and the control grid of the first stage amplifier 2U is connected to the reference voltage source. The cathode of tube .2| is also connected to a suitable biasing divider 29 between bus I8 and bus 25.

A single pole double-throw switch 32 is connected to the bus 25. Terminal 32A of the switch is connected directly to the grounded lead I2 and terminal 32B of the switch is connected through an auxiliary voltage source 'de to the grounded lead I2. In this particular embodiment, the voltage source 34 comprises a pair of series coupled voltage regulator tubes 35, St.

The operation of the circuit described with specific relation to the application mentioned above, is as follows:

With the switch 32 in the position shown in the drawing, an unregulated D. C. voltage of approximately 350 volts is impressed across the input terminals It and Il. Regulation of the output voltage appearing across terminals I9 and I 3 is accomplished in regulator tube I 5, current dow through the tube being a function of the signal impressed on the control grid |513. This signal is derived from the two-stage amplifier formed by tubes 2G, 2l and is, in turn, a function of the signal impressed on the cathode of the firststage tube 25 as it relates to the reference voltage applied to the control grid of the same tube from the reference source 2B. The signal applied to the cathode 2t from the voltage divider 2li is a function of the setting of the movable contact 24A and also of the liuctuations in unregulated input voltage applied to the divider 24 from the feed forward loop 25A and the variations in regulated output voltage applied across the divider 2d from the output lead I8.

The application of a feed forward greatly increases the regulation achieved by the circuit since fluctuations in input voltage are more or less anticipated in advance by the amplier and consequently, by the regulator tube, thereby minimizing iluctuations in output voltage.

With switch 32 in the position shown, the bus 2t is connected directly to the grounded output terminal I3 and a 210 volt regulated voltage will appear across the output terminals I 3, I9 upon appropriate setting of the movable contacts of the voltage dividers 24, 25. To obtain a higher regulated voltage of say 510 volts, the switch 32 is moved to contact the terminal 32B, in which position the bus 26 is connected to the grounded output terminal I3 through the voltage A voltage reference source, in this emi regulator tubes 35, 36. For this specific application, the tubes 55, 3c are 150 volt regulator tubes resulting in an incremental voltage increase across the terminals I3 and I9 of 300 volts. Obviously, other regulator tubes of differing capacity could be selected to achieve different regulated output voltage.

The circuit illustrated in Fig. 2 is more complete than the diagrammatic representation of Fig. 1 but essentially operates on the same principles outlinedabove. Referring to Fig. 2, the circuit is provided with an input transformer le having a primary 56A and a secondary 40B.

. A volt A. C. source i2 is connected to a douf ble pole single throw switch 43 by means of which the 115 volt source may be connected across the entire primary ltA of the transformer or across a fraction of the primary through the auxiliary connection IM.

A rectifier tube d6 is connected across the secondary dB of the transformer di), the lament Current for the rectifier tube being supplied by a second transformer 38, likewise connected across the A. C. source 42. A regulator tube 50 having an anode 55A, cathode 58B, control grid 55C and screen grid 56D is connected by its anode 53A through an l'rC filter 5I to the rectier tube et by a lead i9 to receive the unregulated D. C. output of the rectifier.

As in the circuit of Fig. l, a two-stage amplier 52 is connected so that the plate voltage of the second amplification stage is delivered to the control grid 55C of the series regulator tube 5D. The cathode of the regulator tube 5c is connected to output lead 53 terminating in output terminal 5t and also to a common bus 55 through resistors 55, 5l. A rst voltage divider et is connected between the output lead 53 and a second voltage divider 5I by a feed forward lead 62. The second voltage divider 5I is connected between input lead te and the bus 55. The cathode of the first amplifier stage is connected to the movable contact 55A of the first voltage divider 6E?, providing a feed-back adjustment whereby the output voltage may be set and will act to compensate for changes in the output. The feed forward loop 52 likewise contributes to the signal applied from the divider Se to the cathode of the first amplification stage and compensates for power line changes or any other changes in the unregulated input. A reference voltage gas tube e4 is connected between the output lead 53 through a resistor 63 and bus 55, and thence through a filter network comprising resistor 65 and capacitor 66 to the grid of the first amplification stage.

The common bus 55 is connected to one switch arm of a double pole, double throw switch 68. One terminal 68A of the switch is connected directly to a ground lead 'It terminating in an output terminal 'Il and originating at the center tap of the secondary winding 4GB of the input transformer lit. A second terminal 68B of the switch 68 is connected to the lead l0 through a pair of voltage regulator tubes l2, 13. This arrangement permits the bus 55 to be connected by means of switch arm 68C to the ground output lead 'I either directly or through the voltage regulator tubes l2, 'I3 with the results described in relation to Fig. l. A dropping resistor 'I6 is connected between the lead 139 and a second movable contactor 68C of switch 68. Terminal 68E of switch 58 is connected to the output lead 'I0 through V. R. tubes '12, 'i3 and terminal BSF is dead.

Switches 43 and B8 are ganged so that when switch S8 is positioned with the contactor 68C, engaging terminal 68B and contactor 68D engaging 68E', switch 33 connects the A. C. source 42 across approximately half of the primary 60A of transformer 40, resulting in an increased voltage step up in the transformer. At the same time the dropping resistor 'i6 is connected to the dead terminal 58B" of switch 58. In this position, a 510 volt regulated Voltage will appear across the output terminals 54, TI. When the contactors of switch G3 are positioned to contact the opposite terminals 63A, 58E, respectively, switch d3 is likewise activated to connect the A. C. source l2 across the entire primary 60A of the input transformer. In this position, approximately 350 volts of unregulated voltage is achieved. Also, the bus 55 of what has been referred to as the basic circuit, is connected directly to the output lead l and the dropping resistor 'i5 is connected to the output lead through the V. R. tubes l2, T3. Under these circumstances, the regulated output voltage appearing across terminals :3, 'll will be approximately 210 volts, the exact value being dependent upon the setting of the movable contacts of the voltage dividers Sil, B l. It is signiiicant that once these contacts are set no further adjustment is required when switching from 210 to 510 volt output. rThe purpose of the dropping resistor 'i6 and its connection through the V. R. tubes 12, '13, when the latter are not in circuit between the bus and output lead l0, is to keep these tubes warm, hence, improving their accuracy when they are called into use. Obviously, other means for accomplishing the same purpose may be employed, the illustrated means serving only to show how this may be accomplished without the use of' extraneous voltage sources.

A third transformer is connected to deliver filament current to the series regulator and amplifier tubes. The transformer 80 is a socalled line regulation transformer which will deliver a iixed 6.3 volt filament voltage from the 115 Volt source 42 irrespective of uctuations in the source 42, The use of such a transformer in the present circuit is desirable since the circuit is sensitive to variations in filament voltage.

Although voltage regulator tubes have been shown as auxiliary voltage sources to be coupled to the basic regulator circuit, the invention is not limited to the use of such tubes. Any regulated voltage source is satisfactory. For example, batteries could be used to replace the tubes 72, 73 and would serve the same purpose as these tubes.

As mentioned above, one of the important features of the invention is the unexpected degree of regulation obtained by the combination circuit, i. e., the basic circuit plus the auxiliary Voltage source. Actually, the regulation of the circuit is greater than the algebraic sum of the regulator actions of the two component parts operating independently, and in fact, approaches very closely the performance of the better of the two regulators, namely, the basic circuit. This is true even though the two component parts of the circuit are, when the higher of the two voltages is desired, eiectively in series. This surprising result can be explained by the fact that the basic circuit is iloating, that is, the bus 55 is not directly grounded and any variations in the output of the V. R. tubes l2, 13 resulting from factors other than temperature `6 change, are stabilized in the basic circuit. The resultant improved performance of the voltage regulator tubes, in turn, adds to the regulation characteristics of the combined supply.

By way of an example of this unexpectedly good regulation assume the stabilization ratio of the voltage regulator tubes operating from an unregulated source to be l0, and that of the basic regulator circuit to be 1000. On the basis of simple algebraic summation, 300 volts of the 510 volts are stabilized by a factor of l0 and, since the variation in the 300 volt portion will be dominant by a factor of times the the ratio 300/210, the net stabilization would be expected to be l0 510/300 or 17. In contrast to this predictable regulation factor of 1'7, the actual stabilization achieved in the described circuit is approximately 500. This excellent performance is a direct result of the combination.

I claim:

l. A Voltage regulator circuit for producing a plurality of regulated output voltages from a like number of unregulated input voltages which comprises a basic regulator circuit connected to alternately receive the several input voltages and adapted to produce the lowest regulated output voltage of said plurality, the basic regulator circuit comprising a series connected regulator tube, a two stage amplifier, means connecting the output of the amplifier into the regulator tube, and a feed forward loop for feeding a fraction of the unregulated input voltage to the rst amplifier stage, at least one auxiliary regulated voltage source and means for alternately connecting said basic regulator circuit directly to ground and through said auxiliary regulated voltage source to ground.

2. A voltage regulator circuit for producing a plurality of regulated output voltages from a like number of unregulated input voltages which comprises a basic regulator circuit connected to alternately receive the several input voltages and adapted to produce the lowest regulated output voltage of said plurality, the basic regulator circuit including a regulator tube connected in series between the input and output, a two stage amplifier, means for applying to the first amplification stage a fraction of the unregulated input voltage and a fraction of the regulated output voltage, and means for feeding .the output of the second amplifier stage to the control tube, at least one auxiliary regulated voltage source and means for alternately connecting said basic regulator circuit directly to vground and through said auxiliary regulated voltage source to ground.

3. A voltage regulator circuit for producing a plurality of regulated output voltages from a like number of unregulated input voltages which comprises a basic regulator circuit connected to alternately receive the several input voltages and adapted to produce the lowest regulated :the rst stage, and vmeans for impressing on the cathode ofthe first stage a traction .of the unregulated input voltage .and a'fraction of the regulated output voltage, at least one auxiliary regulated voltage source and means for alternately connecting said basic regulator circuit directly to ground and through said auxiliary regulated voltage source to ground.

4. A voltage regulator circuit 'for producing a plurality of regulated output voltages from a like number of unregulated input voltages which comprises a. basic regulator circuit connected to alternately receive lthe several input voltages and adapted to produce the lowest regulated output voltage oi said plurality, the basic regulator circuit including a series regulator tube having an anode, cathode and control grid and ior impressingT on the control grid a signal proportional to the iuctuation 1in input and output voltage, at least one Aauxiliary regulated voltage source and means .for alternately connecting said first regulator circuit directly to ground and through said auxiliary regulated voltage source to ground.

5. A voltage regulator circuit for producing a pluralit37 of regulated output voltages from a source of unregulated voltage comprising a multiple primary transformer connected to said source to develop a plurality of unregulated voltages across the secondary of the transformer, a rectier connected to the transformer secondary to convert the transformer output to an unregulated D. C voltage, .a series voltage regulator tube having an anode, cathode vand grid, with its anode connected to the `rectifier and its cathode to a regulated voltage output lead, rst and second amplifier stages each having an anode, cathode and control grid, the anode of the first stage being connected to the control grid of the second stage and the anode of the second stage being connected to the control grid Voi the series regulator tube, a first voltage divider connected at one end to said voltage output lead, a second toltage divider connected at one end between the rectifier and the series regulator tube and at the other end to a common bus, a movable contact on said second voltage divider .connected Yto the other end of said irst voltage divider, a movable contact on the iirst voltage divider connected to the cathode of the `first amplifier stage, `a source of reference voltage connected between said output lead and said bus, the control grid of said rst amplier stage being connected to said source, a grounded output terminal, Vat least one auxiliary voltage source .connected .to said grounded output terminal, first switch means connected to said bus for alternately connecting said bus directly to said grounded output terminal and to said auxiliary voltage source, second switch means connected between the multiple primary of said transformer and the source of unregulated voltage for alternately connecting said source across different portions of said primary, and means for synchronizing the operation of the first and second switch means.

6. A voltage regulator circuit for producing a plurality of regulated output voltages from a source of unregulated voltage, a series voltage regulator tube having an anode, cathode and grid, with its anode connected to the source and its cathode to a regulated voltage output lead, iirst and second amplier stages each having an anode, cathode and control grid, the .anode of the first stage being connected tothe control grid of the second stage and the anode of the .second stage vbeing connected to the control grid Aof vthe series regulator tube, a first voltage divider connected at one end to said voltage output lead, a second voltage divider connected at one end between the rectier and the series regulator tube and at the other end to a common bus, a movable contact on Vsaid second voltage divider connected to the other end of said first voltage divider, a movable contact on the rst voltage divider connected to the cathode of the rst amplifier stage, a source of reference voltage connected between said output lead and said bus, the control grid of said iirst amplifier stage being connected to said source, a grounded output terminal, at least one auxiliary voltage source connected to said grounded output terminal, and means for alternately connecting said bus directly to said grounded output terminal and to said auxiliary voltage source.

7. A voltage regulator circuit for producing a plurality of regulated output voltages from a source of unregulated A. C. voltage, a rectier connected to the source to convert the transformer output to an unregulated D. C. voltage, a series voltage regulator tube having an anode, cathode and grid, with its anode connected to the rectifier and its cathode to a regulated voltage output lead, first and second amplifier stages each having an anode, cathode and control grid, the anode of the first stage being connected to the control grid of the second stage and the anode of the second stage being connected to the control grid of the series regulator tube, a first voltage divider connected at one end to said voltage output lead, a second voltage divider connected at one end between the rectier and the series regulator tube and at the other end to a common bus, a movable contact on said second voltage divider connected to the other end of said first voltage divider, a movable contact on the nrst voltage divider' connected to the cathode of the first amplier stage, a source of reference voltage connected between said output lead and said bus, the control grid oi said rst ampliiier stage being connected to said source, a grounded output terminal, at least one auxiliary voltage source connected to said grounded output terminal, and switch means connected to said bus for alternately connecting said bus directly to said grounded output terminal and to said auxiliary voltage source.

8. A voltage regulator circuit for producing a plurality of regulated output voltages from a source of unregulated A. C. voltage comprising la multiple primary transformer connected to said source to develop a plurality of selectable unregulated voltages across the secondary of the transformer, a rectifier connected to the transformer secondary to convert the transformer output to an unregulated D. C. voltage, a series voltage regulator tube having an anode, cathode and grid, with its anode connected to the rectier and its cathode to a regulated voltage output lead, rst and second amplier stages each having an anode, cathode and control grid, the anode of the rst stage being connected to the control grid of the second stage and the anode of the second stage being connected to the control grid of the series regulator tube, a first voltage divider connected at one end to said'voltage output lead, a second voltage divider connected at one end between the rectiner and the series regulator tube and at the other end to a common bus, a movable contact on said second voltage divider connected to the other end of said 9 voltage divider, a movable contact on the first REFERENCES CITED voltage divider connected to the cathode of the The following references are of record m the rst amplifier stage, a source of reference voltme of this patent: age connected between said output lead and said bus, the control grid of said first ampliier stage 5 UNITED STATES PATENTS being connected to said source, a grounded output terminal, at least one auxiliary voltage source Nyegw Bralne AugDatelgm connected to said grounded output terminal, and 2525451 Graves Oct '10 1950 for alternately connecting said bus directly to 215281569 Young e-t' Nov 7" 1950 said grounded output terminal and to said auxill0 iary voltage source.

PAUL S. GOODWIN. 

